2007 Xterra cooling system puzzler

[Bob Kontak]

Originally Posted by drcoastline

I don't know where to go next but the water pump? I would think not if I have heat?

I wanted to see if I had flow through the engine but not sure how to go about that?

Edit: and I would guess maybe the thermostat isn't opening due to the curren temperature here 44 degrees? Although it was in the sixties yetserday. If the thermostat isn't opening no flow through the block correct?

Water will not flow through the block and you will not have heat at least based on old school systems.

Your thermo will open if it's 80F outside.

[drcoastline]

Originally Posted by Bob Kontak

Water will not flow through the block and you will not have heat at least based on old school systems.

Your thermo will open if it's 80F outside.

So since there is heat (when th sytem is full of fluid) thermostat is openin g and water pump is pumping?

[Scott Douglas]

This thread reminds me of a problem I had with an old Alfa Romeo. It had a hose that would bypass the radiator so water would circulate in the block to help warm it up faster. This hose had a spring loaded valve in it that would be opened when the thermostat was closed by the water pressure being pumped by the water pump. When the 'stat opened it would close, diverting the water to the radiator to be cooled. I got hold of another car, same model etc. and it didn't have that diverter valve in the bypass hose. Car ran hotter than normal, especially in the 120* temps out in Palm Springs where I bought it. Put a diverter valve in the system and it worked fine. That along with removing the defunct A/C condenser some idiot mechanic left sitting in front of the radiator when he removed the A/C system helped a lot.
I find it odd that your engine wouldn't circulate coolant in the block until the thermostat opened. I've also never run across an overflow tank that is part of the pressurized system either.
Learnin' stuff every day here on PPOT.
Wish I could help more.

[drcoastline]

Originally Posted by Scott Douglas

This thread reminds me of a problem I had with an old Alfa Romeo. It had a hose that would bypass the radiator so water would circulate in the block to help warm it up faster. This hose had a spring loaded valve in it that would be opened when the thermostat was closed by the water pressure being pumped by the water pump. When the 'stat opened it would close, diverting the water to the radiator to be cooled. I got hold of another car, same model etc. and it didn't have that diverter valve in the bypass hose. Car ran hotter than normal, especially in the 120* temps out in Palm Springs where I bought it. Put a diverter valve in the system and it worked fine. That along with removing the defunct A/C condenser some idiot mechanic left sitting in front of the radiator when he removed the A/C system helped a lot.
I find it odd that your engine wouldn't circulate coolant in the block until the thermostat opened. I've also never run across an overflow tank that is part of the pressurized system either.
Learnin' stuff every day here on PPOT.
Wish I could help more.

I don't know the answer to this. It was a question. Thermostat is 180 degree so Assuming the engine doesnt come up too temp thermostat doesn't open? and coolant doesn't flow?

Again, the initial reason this vehicle failed inspection was it was running cool.

[oldE]

The usual reason for running cool is a thermostat which is stuck open or is opening too soon. I have heard of new thermostats out of the box which were defective in this fashion. The way to test is to immerse the thermostat in water with a thermometer and increase the temperature until the unit opens.
On the other hand, in my experience big temperature differences between the upper and lower hoses can indicate an air bubble at the water pump.
Where is the highest point in the cooling system? Can air be removed at that point?
Best
Les

[Bob Kontak]

Originally Posted by drcoastline

So since there is heat (when th sytem is full of fluid) thermostat is openin g and water pump is pumping?

You did drive it 25 miles. You can't do that with a non-functioning water pump or thermostat.

[Bob Kontak]

Originally Posted by oldE

Where is the highest point in the cooling system? Can air be removed at that point?

Don't think his engine has the bleeder screw.

Found the radiator cap is not a traditional pressure cap. You need to do the pressure test at the plastic tank.

I am almost certain you need a traditional radiator cap on the plastic reservoir. That could be your leak?

[fastfredracing]

Me thinks you need to find the source of the escaping coolant . This will be your huckleberry .
You know your system does not hold pressure, you also know that you are loosing coolant somewhere , you have stated that you have seen it after each no heat event .
Clean it up , fill it then be patient and let it run till you can locate where it is coming out .
Really sounds like something is up with your expansion tank . It would be the weakest link

[drcoastline]

Originally Posted by fastfredracing

Me thinks you need to find the source of the escaping coolant . This will be your huckleberry .
You know your system does not hold pressure, you also know that you are loosing coolant somewhere , you have stated that you have seen it after each no heat event .
Clean it up , fill it then be patient and let it run till you can locate where it is coming out .
Really sounds like something is up with your expansion tank . It would be the weakest link

That's what I am thinking as well. Based on Bob's recommendation I thought I would take it all that mess apart and check the hoses, tank, etc before buying a new one. Everything seemed to be in order.

The whole set up above is only $62.00 from Parts Geek so I think I am just going to get it. If for no other reason to rule it out.

[drcoastline]

Originally Posted by Bob Kontak

Don't think his engine has the bleeder screw.

Found the radiator cap is not a traditional pressure cap. You need to do the pressure test at the plastic tank.

I am almost certain you need a traditional radiator cap on the plastic reservoir. That could be your leak?

Hi Bob, yes you are correct. I forgot to mention that I put the pressure cap on but then replaced it with the traditional cap.

I did do a pressure test at the tank. First with the pressure tool. It held pressure. Then yesterday when I took everything apart I tested the parts independantly. Tank, each hose.

[drcoastline]

Originally Posted by Bob Kontak

You did drive it 25 miles. You can't do that with a non-functioning water pump or thermostat.

I was thinking that as well. But looking for reinfrcement from the gang. In actuality I went 50 miles. 25 on direction 25 back. But I stopped in the middle and checked the system. Then it sat about an hour before I returned.

[Scott Douglas]

Going back to your original post, how far had you driven the car before going to get it inspected?
Did you consider it to be up to temperature when it was inspected?

[drcoastline]

Originally Posted by Scott Douglas

Going back to your original post, how far had you driven the car before going to get it inspected?
Did you consider it to be up to temperature when it was inspected?

Including driving to other places before going to inspection I would estimate 10-12 miles? I did stop an turn it off a few times but I think it would have been up to temp before inspection.

So per my post above I order a new expansion tank including the hoses earlier today. I needed coolant so went to my nearby Advance. While there I decide for the hell of it to get another new radiator cap (16lb) and then decide to get a new cap for the expansion tank.

When the counter guy enters the information for a cap for the expansion tank, reservior, overflow tank. Various searchs nothing matches. So he goe back to the radiator caps.

The list has three cap One 16lb with a relief handle I already have that one. A flat cap no indication of lbs. and lastly the cap I bought which looks like a standrad 16lb cap. At this time the counter guy notices on the screen the 16lb. caps indicate Reservior caps and the flat cap says radiator.

Now I am thinking the caps are backwards. I buy both caps install them, start the vehicle and I get slight pressure in the hoses within a few minutes. Not a lot but some resistance. I top off the radiator and drive back to the little hill at the beach entrance where I burp the system. No wetness at all around the expansion tank. Some condenstion behind the radiator cap on the shroud. Still mild pressure on the hoses. I opened the cap the radiator is full. I replace the radiator cap and squeezed the upper hose, I can hear air escaping around the cap. This would indicate the moisture on the shroud.

I am now starting to conclude the new radiator is defective.

[Bob Kontak]

Originally Posted by drcoastline

Hi Bob, yes you are correct. I forgot to mention that I put the pressure cap on but then replaced it with the traditional cap.

So there is no confusion. This is the kind of cap that goes on the reservoir based on my understanding.

[drcoastline]

Originally Posted by Bob Kontak

So there is no confusion. This is the kind of cap that goes on the reservoir based on my understanding.

If that is the 16lb pressure cap you would be correct. I just found a thread on an Xterra sight that conforms this.

[Bob Kontak]

Originally Posted by drcoastline

If that is the 16lb pressure cap you would be correct. I just found a thread on an Xterra sight that conforms this.

Just a random pic of a radiator cap. I used the term pressure cap and traditional radiator cap.

Pic is of a traditional radiator cap. Cap on radiator must be just a sealing cap. No relief function.

[Scott Douglas]

Can you take a picture of the radiator neck for us?

[drcoastline]

Originally Posted by Bob Kontak

Just a random pic of a radiator cap. I used the term pressure cap and traditional radiator cap.

Pic is of a traditional radiator cap. Cap on radiator must be just a sealing cap. No relief function.

Yes, the radiator has a regular cap, the tank has a relief cap. I should say now they do, they were reversed.

[drcoastline]

Originally Posted by Scott Douglas

Can you take a picture of the radiator neck for us?

Yes, I will post in the morning.

[drcoastline]

Originally Posted by Scott Douglas

Can you take a picture of the radiator neck for us?

This is the radiator I removed from the vehicle.